The present invention relates generally to data processors and more particularly to electronic calculators. It is commonly realized that the number of different functions performed by a calculator is often limited by the number of available calculator keys or available keyboard configurations, each configuration representing a combination of different keys of the keyboard. Generally, a key may be used to perform only a limited number of functions, viz., those functions identified by labels located on or near the key. It is often difficult to place more than three such marks on or near a key to identify that key for multiple use. Furthermore, keyboards having a plurality of keys limit the size of the calculator because not only must the keys be finger-size, but the calculator itself must be large enough to contain the keys and to legibly display the labels of the keys.
A device that would be capable of not only entering data but also of entering and executing commands and entering, storing and executing programs without the above-mentioned keyboard limitations would, therefore, be very useful and desirable.